Atherosclerosis and blood clottingEdexcel International A Level Biology: Subtopic test

1. 1
   A post-mortem examination of the coronary artery of a man who died of a heart attack showed a raised, fatty deposit in the artery wall that had narrowed the lumen.

   (a)

   Which event is the first stage in the development of atherosclerosis?

   [1 mark]

   • AA fibrin mesh forms across the artery
   • BDamage to the endothelium lining the artery
   • CFoam cells accumulate in the artery wall
   • DThe plaque ruptures and exposes collagen

   (b)

   Which type of cell migrates into the artery wall during the inflammatory response and takes up LDL cholesterol to form foam cells?

   [1 mark]

   • APlatelets
   • BRed blood cells
   • CLymphocytes
   • DMacrophages

   (c)

   Explain how atherosclerosis can lead to raised blood pressure.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Blood clotting is a series of reactions. In a laboratory demonstration, a technician starts the clotting of a plasma sample by adding thromboplastin and calcium ions.

   (a)

   Which cell fragments release thromboplastin when a blood vessel is damaged?

   [1 mark]

   • APlatelets
   • BRed blood cells
   • CPhagocytes
   • DLymphocytes

   (b)

   Which statement about the clotting reactions is correct?

   [1 mark]

   • AThrombin is converted to prothrombin by fibrin
   • BFibrin is converted to fibrinogen by thrombin
   • CProthrombin is converted to thrombin by thromboplastin
   • DFibrinogen is converted to thromboplastin by thrombin

   (c)

   Explain why it is important that fibrinogen is soluble but fibrin is insoluble.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A 62-year-old woman with raised blood pressure and a high blood cholesterol concentration is admitted to hospital with a heart attack. An angiogram shows that one of her coronary arteries is blocked by a blood clot at the site of an atheromatous plaque.

   (a)

   Explain how the atheromatous plaque could have led to the formation of the blood clot.

   [3 marks]

   (b)

   Explain how the blocked coronary artery causes a heart attack, and why her raised blood pressure increases the risk of the endothelium being damaged.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A pathologist is preparing teaching material for medical students on how an artery wall responds to damage and how the body stops bleeding from a cut.

   (a)

   Describe how an atheroma develops in an artery, starting with damage to the endothelium, and explain how it can reduce the oxygen supply to heart muscle.

   [6 marks]

   (b)

   Explain how the blood clotting mechanism stops blood loss from a cut, and how the same mechanism can lead to cardiovascular disease.

   [6 marks]

   Total for question 4: 12 marks

End of questions